Help identifying noise from intake manifold

Just got this 2002 access cab 4.7L V8 5 days ago. It's had zero issues until midway through my most recent hour long trip when halfway through I noticed this noise. It has no check engine lights and at the same time I am noticing an oil leak on the left side of the engine. Attached is a YouTube video of the noise and if anyone can help me figure out what's causing it I would greatly appreciate it, thanks!
https://youtube.com/shorts/Dprf2yvT_2k?si=q1-iBW41aUesgxkY

 

Valve cover leaks are common (re: oil leak)

have you read this thread yet? https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

 

Loose fan maybe? New FGT - when was the timing belt last changed?

 

And I don’t recognize the noise, but you’d be doing yourself a favor to get the K&N filter out of there. It sounds almost like something thumping on a hollow tube, or pumping air into something.

What have you checked on the car so far, and when was the last time the timing belt was done?

 

Thank you I have not read that thread yet. I believe this is likely the case given the location of the oil.

 

I don't think it's the fan just because in person its clearly coming around the engine area.

 

I agree I had been unaware of this sort of thing until now. The old filter doesn't look like it's been taken care of and doesn't look like it could be reoiled and reused. I bought a replacement filter for the time being that should be here in 2 days but I agree that eventually I do want to take the whole thing out and put in an OEM system. Would you happen to know what it would cost to do that? Here are pictures of the system for reference;

 

You just need to find a donor vehicle and snag the OEM assembly off it. Any 2000-2003 donor with a v8 should be a good option.

Meanwhile, I’d really be looking around for loose vacuum hoses, cracked vacuum hoses, checking your fluids, check the PCV valve. Pop the “v8” cover off, check those hoses. It sounds like something breathing/gurgling, but I can’t tell if it’s liquid or air that’s burping. Is there appropriate fluid in the radiator overflow? How’s your oil level? Power steering fluid?

If you can, isolate its location. See if it’s louder above or below the engine. If above, is it louder on the left or right side of the engine? Once you have a side, is it louder closer to the radiator or firewall?

Good part is, it’s an ‘02. So no extra fun stuff like SAI to deal with.

 

Yup those aftermarket intakes are crap and offer no power gains.

 

Got you I guess I'll be on the lookout for a donor, all fluids are good however there's a chance that the oil has leaked out in the few days since it's been changed and that's causing the noise. As far as I can tell it's coming from the middle of the bay and it's louder from the top.

 

Update, loosing coolant but the radiator looks good and I am definitely leaking oil from both valve cover gaskets.

 

Ignore the valve covers for now, that’s so totally normal, we all have it. I can link you up with a single reply on here that will give you all the info you need to know about.

Ok so the big question is where are you losing coolant from? Because it sounds like air/water bubbles. Do you see any coolant anywhere? I’m guessing it’s maybe the coolant crossover tube.

 

Taking this from the mega thread of info every gen1 owner needs to know:

• Coolant leaks: Three common causes: One is the is the gasket behind the thermostat housing, another is the coolant crossover at the rear of the block, and last but not least, old radiators is another source. Here's a list of things to check if you're losing coolant. For repairing the leak behind the t-stat housing, check this out. For the coolant crossover tube issue, you'll likely find coolant at back of the block, near where the trans and engine meet, check this reply for video/fix. This reply contains links to three other off-brand/odbball leak cases. For radiator leaks, this is one example of a tiny one - always replace with Denso brand radiator, and know different cab types use different sizes, careful where you order, scAmazon especially tends to deliver damaged products often (RockAuto has a spotless record with forum members). Proactive radiator replacement is wise. The transmission line routes through the bottom of the radiator ... go look up "pink milkshake", ithappens in these trucks.

 

I think it sounds like a loose cat shield...

 

It's a bit hard to tell with all the oil so I'm thinking I'll just go get a cheap pressure tester to locate the coolant leak and go from there.
Thankfully with information in the valve cover gaskets changing thread linked in the megathread
I did go ahead and order everything from Toyota to replace the valve cover gaskets, spark tube gaskets, PCV valve and grommet, the fipg for halfmoons and spark plugs while I'm at it.

 

I'll check that too when I go out thanks!

 

Update, I think the noise was coming from 2 detached evap hoses. I've reattached them where I circled on the picture and zip tied them because they slid off fairly easily. I'm fairly unfamiliar with this system and I'm thinking that any small amount of pressure could have just blown the hoses off. I've not heard the sound since reattaching them but I've also only moved the truck a few hundred feet. Could this have potentially been the noise? It sounded like it was coming from the top of the manifold right under the nameplate.sparkplugs have all been changed (the old ones were worn very far down) and fan/serpentine belt were all checked and the noise continued. Additionally I tightened the valve covers just for the time being until all of my gaskets come in because they were barely even torqued. I'm thinking the gaskets being flattened and the vibration of the engine could have just worked those bolts out.

 

Evap hoses. That's the charcoal canister and vacuum pump box in the 2nd box. At this age, the vacuum hoses are pretty worn and stretched. I've slowly started replacing mine at this point and my truck is newer with way fewer miles. Nature of the beast.

 

I replaced most of my hoses that are in your photo. OEM hoses are pricey - be forewarned.

 

I've had those come off too. I cut the ends off and reattached and zip tied and one came off again later. Ended up replacing with new generic hose (I forget what size) and all good now.

 

So unfortunately after hearing the noise again, I checked to see if the hoses came off again and they had not. So I'm sort of back to square one other than the fact that I have figured out that the sound is coming from the intake manifold. The idle is very rough with rpms going up and down periodically.

 

I didn't want to go there, but I'd suspect the intake manifold gasket may be at EOL. No huge crushing deal if so, but the only way to figure out if that's the case is to pop off the intake manifold. I suspect you may find this. That being said, learn from others on here, including this guy, who went through 2 intake manifold gaskets before learning: That's a part you'll want to buy from either from FelPro or get OEM. I know the first one (shown) was ITM brand. The 2nd was either Reinz or Back-Arnley? Or maybe I'm wrong about a 2nd time. Anyway, BMF finally broke down and bought OEM this time, a few days ago. I know OEM is expensive, but OEM isn't as expensive as buying two other brands, then having to buy OEM because non-OEM sucked, and, oh .... having to do the job 2-3 times! If you want someone to bounce thoughts off of ... @bmf4069 is good people, and can probably lend a handful of words to it.

Edit: Found the post where the original ITM gasket was installed. He did the VC and intake gaskets at the same time. https://www.tundras.com/threads/intake-manifold-and-valve-cover-gaskets.37347/

 

Back in the day we used to use a propane torch with no flame to detect manifold leaks. When the vaccum leak draws in the propane it enriches the mixture slightly and speeds up the engine. Personally I's spend the money for OEM gaskets.

 

Okay I apologize for this going all over the place but I've now checked it with an engine stethoscope and in terms of noise and physical clunks I'm feeling it most in the throttle body. Is there anything in the throttle body that could be causing this noise or could that still point to the intake and gaskets? Just trying to accurately diagnose the most important issue before buying more parts and spending more money.

 

Update, I just cleaned out the throttle body with some gumout. It was very dirty and had a ring of gunk on the wall where it meets the butterfly valve. I think the old k&n filter was so old and neglected that it was just clogging the throttle body. It must have been cleaned just before selling and then in the few days after started gunking up again. I also just replaced the filter so below are attached pictures of the old and new filter comparison. As well as my rag after cleaning throttle body. I am still planning on getting an OEM air intake but hopefully this new filter should suffice for the time being. Truck is idling smooth as butter now and I feel like I've gotten back a little more power which is likely also a result of having an unclogged intake filter. The noise is intermittent and hard to replicate at points so there's a chance I'll update later saying the problem isn't fixed but I feel confident at the moment that this was the issue.

 

You might consider doing this>https://www.tundras.com/threads/throttle-body-cleaning-and-relearning-psa-how-to.121328/

 

That sounds like your intake manifold gasket. Does the truck surge when you're in drive holding the brake? It did have a more metallic sounds and was faster than mine, but those pops sounded like what mine did. It would also hunt for idle. @JakeJake brought buy his propane bottle and when we put the nozzle between the runners the idle smoothed out. I'd try that.

Also, @shifty` the second brand was ultra.

 

Anything flammable would work for this diagnostic. Starting fluid, carb cleaner etc. I would recommend short bursts if you are using a liquid and keep a rag or other fire suppression handy!

The rough idle and popping noise from the video is very similar to what @bmf4069 truck was doing. I think the metallic sounding part of that noise is whatever the air from the intake leak is hitting. Maybe the intake cover or one of the heat shields on the exhaust manifold?

 

That was my basic thought on sounds - almost the sound of someone slapping a flat piece of rubber onto the end of round steel tubing. Hollow echoey sound. But I was having trouble trying to picture what'd be wide enough to slap the intake port that hard/wide.

 

Since I haven't fixed mine I could probably just get a video of it.

Wait, I already made one when it did it last time.

https://youtu.be/NxYVy9Gntu8?si=KE9KtQ7wQ3oFF-rE